Battery Charging Control Methods, Electrical Vehicle Charging Methods, Battery Charging Control Apparatus, and Electrical Vehicles

ABSTRACT

Battery charging control methods, electrical vehicle charging methods, battery charging control apparatus, and electrical vehicles are described. In one arrangement, battery charging control methods include accessing price information for electrical energy supplied by an electrical power distribution system and controlling an adjustment of an amount of the electrical energy from the electrical power distribution system used to charge a rechargeable battery at different moments in time using the price information. Other arrangements are described.

GOVERNMENT RIGHTS STATEMENT

This invention was made with Government support under contractDE-AC0676RLO1830 awarded by the U.S. Department of Energy. TheGovernment has certain rights in the invention.

TECHNICAL FIELD

The present invention, in various embodiments, relates to batterycharging control methods, electrical vehicle charging methods, batterycharging control apparatus, and electrical vehicles.

BACKGROUND

The use of hybrid electric vehicles is widespread. In these vehicles,batteries are recharged by the vehicle itself without relying on aplug-in connection to an electrical power distribution system. A newgeneration of vehicles is now being developed, however, that will relyon drawing electrical energy from the electrical power distributionsystem to charge rechargeable batteries. Such vehicles include plug-inhybrid electric vehicles and plug-in electric vehicles. These vehiclesmay begin charging upon being connected to the electrical powerdistribution system.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the disclosure are described below withreference to the following accompanying drawings.

FIG. 1 is a block diagram of a battery system and an electrical powerdistribution system according to one embodiment.

FIG. 2 is a block diagram of a controller according to one embodiment.

FIG. 3 is an illustrative representation of an electrical vehiclecoupled with a battery charging apparatus and an electrical powerdistribution system according to one embodiment.

FIG. 4 is a flow chart of a battery charging method according to oneembodiment.

FIG. 5A is a graph illustrating price information according to oneembodiment.

FIG. 5B is a graph illustrating resting time information according toone embodiment.

FIG. 5C is a graph illustrating schedule information according to oneembodiment.

FIG. 5D is a graph illustrating schedule information according toanother embodiment.

FIG. 5E is a graph illustrating schedule information according to oneembodiment.

DESCRIPTION

This disclosure is submitted in furtherance of the constitutionalpurposes of the U.S. Patent Laws “to promote the progress of science anduseful arts” (Article 1, Section 8).

At least some aspects of the present disclosure are directed towardsmethods and apparatus for charging rechargeable batteries. In someembodiments described herein, price information is used during chargingof the rechargeable batteries. In one specific embodiment describedbelow, price information regarding prices of electrical energy suppliedby an electrical power distribution system is used to control one ormore charging operations of the rechargeable batteries. The disclosuredescribes, in some example embodiments herein, methods and apparatus forcharging batteries of an electrical vehicle. In other embodiments, therechargeable batteries may be used in applications other than vehicleapplications. Other aspects and embodiments are described herein and areencompassed by the claims.

Referring to FIG. 1, one embodiment of a battery system 12 is showncoupled with an electrical power distribution system 10. Although onlyone battery system 12 is shown in the embodiment of FIG. 1, numerousadditional battery systems 12 may be coupled with electrical powerdistribution system 10 in other embodiments. In one embodiment,electrical power distribution system 10 is arranged to provideelectrical energy to the battery system 12 to charge one (or more ifpresent) rechargeable batteries 16 of the battery system 12. In someembodiments described below, the rechargeable battery or batteries 16may be utilized to power an electrical vehicle (e.g., plug-in hybridelectric vehicle (PHEV), electric vehicle (EV)). Rechargeable batteries16 may be used in other apparatus and/or in different applications inother embodiments.

In one embodiment, electrical power distribution system 10 comprises anyappropriate electrical energy delivery system configured to deliverresidential, commercial, industrial, or other electrical energy from asupply to customers or consumers. Electrical power distribution system10 is arranged to provide electrical energy for consumption by batterysystem 12, for example, for operation and for recharging therechargeable batteries 16. Electrical power distribution system 10 maybe arranged as one or more source (e.g., generator or otherconstruction) configured to supply electrical energy. Generators may beindividually taken on-line (e.g., on grid) or off-line (e.g., off grid),or the output thereof may be adjusted, according to the usage of theelectrical energy. Electrical power distribution system 10 includes adistribution grid which may comprise a plurality of switching stations,transformers, and transmission lines arranged to transmit electricalenergy from sources to loads, such as the battery systems 12. Thetransmission lines may transmit the electrical energy using high voltagelines spanning across vast distances (e.g., hundreds or thousands ofmiles) between distant geographic locations in some arrangements.

In addition to remotely located generators, electrical powerdistribution system 10 may include one or more generators located nearbattery system 12. For example, in one embodiment, electrical powerdistribution system 10 may include one or more generators located in thesame neighborhood as battery system 12 and the one or more generatorsmay be configured to provide power to some or all of the neighborhood.In another more specific example, electrical power distribution system10 may include one or more generators located in or adjacent to astructure to which battery system 12 is connected. The one or moregenerators may be configured to provide power to the structure. In somecases, the one or more generators may be configured to provide power tothe structure in the event that another power generator of electricalpower distribution system 10 is disabled or in the event thattransmission lines that typically provide power to the structure aredisabled. In some cases, the one or more generators may be located in oradjacent to residential, commercial, industrial, or other structures.

In one implementation, electrical power distribution system 10 isarranged to provide alternating current electrical energy at a systemfrequency of 60 Hz. System frequency is the frequency of system voltage.Electrical power distribution system 10 may provide electrical energy atexemplary voltages of 120/240 VAC, 120/208 VAC, 277/480 VAC or otherappropriate voltages in example arrangements.

As mentioned above, battery system 12 includes one or more rechargeablebatteries 16 in the described embodiment. Rechargeable battery 16 mayhave different configurations in different implementations (e.g., leadacid, nickel hydride, lithium ion in some examples). During use, thestate of charge of rechargeable battery 16 decreases, and electricalenergy from electrical power distribution system 10 is configured tosupply electrical energy for recharging of the rechargeable battery 16to an increased state of charge.

In addition, battery system 12 also includes a battery chargingapparatus 14 in one embodiment. In the depicted embodiment, batterycharging apparatus 14 is coupled between electrical power distributionsystem 10 and rechargeable battery 16. Battery charging apparatus 14 isconfigured to implement charging operations of rechargeable battery 16using the electrical energy from the electrical power distributionsystem 10 in one embodiment.

In the depicted embodiment, battery charging apparatus 14 includes acharger 18 and a controller 20. Charger 18 is configured to receiveelectrical energy from electrical power distribution system 10 and toprovide the electrical energy to rechargeable battery 16 to chargerechargeable battery 16. In doing so, charger 18 may, in one embodiment,alter a form of the electrical energy received from electrical powerdistribution system 10 and provide the altered electrical energy torechargeable battery 16. For example, charger 18 may alter the voltageof the electrical energy and/or may alter the electrical energy to beDirect Current (DC) electrical energy rather than AC electrical energy.

As discussed herein according to one embodiment, charger 18 can applydifferent amounts of electrical energy to the rechargeable battery 16 atdifferent moments in time. Furthermore, controller 20 may control whenand at what rate charger 18 applies electrical energy to rechargeablebattery 16 in one embodiment.

In one embodiment discussed in additional detail below, controller 20 isconfigured to access price information regarding prices of theelectrical energy supplied by electrical power distribution system 20.The price information may describe prices of the electrical energy(e.g., in cents per kilowatt hour, in one embodiment). For example, theprice information may describe future prices of the electrical energyover a future period of time. In some cases, an operator of electricalpower distribution system 10 may alter the price for electrical energysupplied by electrical power distribution system 10 over time. Forexample, the price of the electrical energy may be higher during the daywhen there is greater aggregate consumption of electrical power than atnight. In one embodiment, the operator may charge several differentprices during the course of a twenty-four hour period. Accordingly, inone embodiment, the price information may describe hourly prices of theelectrical energy over a future twenty-four hour period. The prices mayvary from hour to hour. Controller 20 may additionally access updates tothe price information as described in more detail below.

Controller 20 may access the price information via a price informationsource 22. Price information source 22 may be embodied in many differentforms. In one embodiment, price information source 22 may be an articleof manufacture which can contain, store, or maintain the priceinformation. For example, price information source 22 may be a USBdrive, floppy diskette, zip disk, hard drive, random access memory, readonly memory, flash memory, cache memory, and/or other configurationcapable of storing the price information. The electrical powerdistribution system 10 may program the article of manufacture with theprice information and then couple the article of manufacture tocontroller 20.

In another embodiment, price information source 22 may include one ormore of a server, computer, or other data device storing the priceinformation that may be in communication with controller 20 via acommunications network. For example, price information source 22 may bea server on the Internet and controller 20 may be connected to theInternet via wired and/or wireless communication. In other arrangements,the server may be located on a private network and controller 20 maycommunicate with the server via wired and/or wireless communication(e.g., via a Power Line Carrier (PLC) network). In another arrangement,a power meter of electrical power distribution system 10 may compriseprice information source 22 and controller 20 may be in communicationwith the meter, for example via a PLC network.

In one embodiment, Controller 20 may use the price information tocontrol charger 18, as is further discussed below. For example, usingthe price information, controller 20 may increase or decrease the amountof electrical energy which is provided by charger 18 to chargerechargeable battery 16 in one embodiment. In one more specific example,controller 20 may use the price information to determine at least onewindow of time during which controller 20 may allow charger 18 to chargerechargeable battery 16. The window of time may include one or more hoursegments of a twenty-four hour period during which the price of theelectrical energy supplied by electrical power distribution system 10 islower compared with other windows of the twenty-four hour period.Optimizing the cost of charging rechargeable battery 16 in this mannermay be economically advantageous to the person or entity paying for theelectrical energy consumed in charging rechargeable battery 16.

For example, battery charging apparatus 14 may be connected toelectrical power distribution system 10 at 3:00 PM and controller 20 maydetermine (e.g., using a present state of charge of rechargeable battery16) that rechargeable battery 16 should be charged for six hours duringa twenty-four hour period, the twenty-four hour period beginning at 3:00PM. Controller 20 may determine, based on the price information, thatcharging rechargeable battery 16 from 9:00 PM to 3:00 AM will result inthe lowest possible cost available during the twenty-four hour period.In some cases, there may be several windows of time during thetwenty-four hour period that may also result in the lowest possiblecost. For example, the cost of charging from 10:00 PM to 4:00 AM may bethe same as the cost of charging from 9:00 PM to 3:00 AM. Of course,periods of different lengths and other resolutions of price informationcould alternatively be used. For example, if the price informationdescribes prices of a future twelve-hour period with half-hourgranularity, controller 20 may select a charging window based onhalf-hour segments of time (e.g., 8:30 PM to 2:30 AM). In anotherexample, plural non-continuous windows occurring at different times ofthe day may be used.

Controller 20 may also be configured to access information regardingrechargeable battery 16 and to control an amount of the electricalenergy used to charge rechargeable battery 16 and/or a time of chargingby charger 18 using the accessed information. In addition, controller 20may access other information for use in controlling the rate and/or timeof charging. For example, in one embodiment, controller 20 maycommunicate with charger 18 to access information related to a currentcharge state of rechargeable battery 16, a temperature of rechargeablebattery 16, and/or a capacity of rechargeable battery 16.

Controller 20 may also access user-inputted information (e.g., a desiredpoint in time in the future for the battery 16 to be fully charged) tocontrol the amount of electrical energy used to charge rechargeablebattery 16 and/or a time of charge in illustrative examples. Additionalinformation may also be used by controller 20 to control the charging.

Referring to FIG. 2, one embodiment of controller 20 is shown. Theillustrated example controller 20 includes processing circuitry 22,storage circuitry 24, an external interface 26 and a user interface 28in the depicted embodiment. Controller 20 may include more, less, and/oralternative components in other embodiments.

In one embodiment, processing circuitry 22 is arranged to process data,control data access and storage, issue commands, and control otherdesired operations. For example, processing circuitry 22 is configuredto access price information regarding prices of electrical energysupplied by electrical power distribution system 10, informationregarding a state of charge of rechargeable battery 16, anduser-inputted information in one embodiment. Processing circuitry 22 mayutilize the accessed information to control charging operations ofcharger 18 with respect to rechargeable battery 16 in one embodiment.

Processing circuitry 22 may comprise circuitry configured to implementdesired programming provided by appropriate media in at least oneembodiment. For example, processing circuitry 22 may be implemented asone or more of processor(s) and/or other structure configured to executeexecutable instructions including, for example, software and/or firmwareinstructions, and/or hardware circuitry. Exemplary embodiments ofprocessing circuitry 22 include hardware logic, PGA, FPGA, ASIC, statemachines, and/or other structures alone or in combination with aprocessor. These examples of processing circuitry 22 are forillustration and other configurations are possible.

Storage circuitry 24 is configured to store programming such asexecutable code or instructions (e.g., software and/or firmware),electronic data, databases, or other digital information and may includeprocessor-usable media. For example, processing circuitry 22 may controlstorage circuitry 24 to store information accessed from system 10,rechargeable battery 16 and/or user-inputted information in oneembodiment.

Processor-usable media may be embodied in any computer programproduct(s) or article of manufacture(s) 25 which can contain, store, ormaintain programming, data and/or digital information for use by, or inconnection with, an instruction execution system including processingcircuitry in the exemplary embodiment. For example, exemplaryprocessor-usable media may include any one of physical media such aselectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor media. Some more specific examples of processor-usablemedia include, but are not limited to, a portable magnetic computerdiskette, such as a floppy diskette, zip disk, hard drive, random accessmemory, read only memory, flash memory, cache memory, and/or otherconfigurations capable of storing programming, data, or other digitalinformation.

At least some embodiments or aspects described herein may be implementedusing programming stored within appropriate storage circuitry 24described above and/or communicated via a network or other transmissionmedia and configured to control appropriate processing circuitry. Forexample, programming may be provided via appropriate media including,for example, embodied within articles of manufacture. In anotherexample, programming may be embodied within a data signal (e.g.,modulated carrier wave, data packets, digital representations, etc.)communicated via an appropriate transmission medium, such as acommunication network (e.g., the Internet and/or a private network),wired electrical connection, optical connection and/or electromagneticenergy, for example, via a communications interface, or provided usingother appropriate communication structure. Exemplary programmingincluding processor-usable code may be communicated as a data signalembodied in a carrier wave in but one example.

External interface 26 is arranged to implement external communicationsand/or data acquisition of controller 20. For example, externalinterface 26 may be coupled with price information source 22 and charger18 in one embodiment. External interface 26 may be implemented as anetwork interface card (NIC), serial or parallel connection, USB port,FireWire interface, flash memory interface, floppy disk drive, or anyother suitable arrangement.

User interface 28 is configured to interact with a user includingconveying data to a user (e.g., displaying data for observation by theuser, audibly communicating data to a user, etc.) as well as receivinginputs from the user (e.g., tactile input, voice instruction, etc.).Accordingly, in one exemplary embodiment, user interface 28 may includea display (e.g., cathode ray tube, LCD, etc.) configured to depictvisual information and an audio system as well as a keyboard, mouseand/or other input device. Any other suitable apparatus for interactingwith a user may also be utilized. In one arrangement, a user may inputinformation to control the charging by charger 18. For example, the usermay specify a point of time in the future in which the battery 16 is tobe fully charged.

Referring to FIG. 3, one embodiment of charging operations of batterysystem 12 (illustrated in FIG. 1) is described with respect to a load inthe form of an electrical vehicle 34 which includes one or morerechargeable batteries 16. Vehicle 34 may be at least partially poweredby an electric motor (not illustrated). The electric motor may consumeelectrical energy stored by rechargeable battery 16 to, at least inpart, provide motive power to propel vehicle 34.

The arrangement of battery system 12 in FIG. 3 is illustrative forexplanation of some aspects of the disclosure and other arrangements arepossible. For example, battery charging apparatus 14 of battery system12 may be installed at home, work, or any other location where it isdesirable to implement charging of rechargeable battery 16 andelectrical energy from electrical power distribution system 10 isavailable for consumption. Although FIG. 3 depicts rechargeablebatteries 16 in electrical vehicle 34, rechargeable batteries 16 chargedby battery charging apparatus 14 may be utilized in differentapplications other than electrical vehicles 34.

Furthermore, one or more components of the battery system 12 may beimplemented differently in other embodiments. For example, batterycharging apparatus 14 may be located onboard vehicle 34 in someimplementations. In other arrangements, charger 18 may be locatedonboard vehicle 34 and controller 20 may be located offboard vehicle 34.In addition, rechargeable batteries 16 may be removable from vehicle 34(or the housing of other loads) and coupled with charger 18, which isnot located on the vehicle in some embodiments.

Vehicle 34 may include a climate system 36. Climate system 36 may beconfigured to modify a temperature associated with vehicle 34. Forexample, climate system 36 may include an air conditioner for cooling acabin of vehicle 34. Alternatively or additionally, climate system 36may include a heater for heating the cabin. In one embodiment, climatesystem 36 may measure and/or monitor one or more temperatures associatedwith vehicle 34 and may provide information describing the measuredand/or monitored temperatures to controller 20 and/or charger 18. A userof vehicle 34 may provide a desired temperature (e.g., a desired cabintemperature) to vehicle 34. In some configurations, climate system 36may have access to information describing the desired temperature.

In one arrangement, climate system 36 may be configured to heat and/orcool rechargeable battery 16. Doing so may be helpful in extreme weatherconditions. For example, if the temperature is very cold, climate system36 may heat rechargeable battery 16 to improve the performance ofrechargeable battery 16. Similarly, if the temperature is very hot,climate system 36 may cool rechargeable battery 16. Heating and/orcooling rechargeable battery 16 may make charging rechargeable battery16 more efficient or may improve the usable life of rechargeable battery16 in some embodiments.

As was described above, controller 20 may be onboard vehicle 34 in oneembodiment. If controller 20 is onboard, vehicle 34 may be connected toelectrical power distribution 10 via a simple electrical cable and mightnot require any circuitry between vehicle 34 and electrical powerdistribution 10 other than the cable. In this embodiment, controller 20may communicate with charger 18 and/or climate system 36 using wiredand/or wireless connections (e.g., via a Controller Area Network (CAN)bus onboard vehicle 34 that facilitates communication between devices ofvehicle 34). For example, controller 20 may retrieve temperatureinformation from climate system 36. Furthermore, controller 20 maycommunicate with other devices onboard vehicle 34 (e.g., a navigationsystem, vehicle computer, etc.).

In another embodiment, controller 20 may be offboard vehicle 34. Ifoffboard, controller 20 may communicate with charger 18, climate system36, and/or other devices of vehicle 34 using one or more wired and/orwireless connections (e.g., via a ZigBee wireless connection, Power LineCarrier (PLC) connection, a cable having a J1772 SAE standard five-pinplug plugged into vehicle 34, or any other suitable arrangement). In oneembodiment, controller 20 may be built into a cable used to connectelectrical vehicle 34 to electrical power distribution system 20. Inthis embodiment, controller 20 may appear to be a “bump” in the cable.Any suitable communication system and power delivery system may be usedto transfer communications, data, and energy between system 10 andbattery system 12.

As was described above, controller 20 may include user interface 28. Auser may communicate information to controller 20 via user interface 28such as a desired time of charge completion, a desired state of chargeof the battery at time of charge completion (e.g., 50% charged, 80%charged, 100% charged, etc.), a desired temperature for vehicle 34,whether to pre-heat or pre-cool vehicle 34 to the desired temperature,etc. In one embodiment, user interface 28 may be integrated with vehicle34 and may be used for purposes other than communicating informationrelated to charging rechargeable battery 16. For example, user interface28 may also be used to control an entertainment system of vehicle 34 ora navigation system of vehicle 34.

As discussed above with respect to FIG. 1, controller 20 is configuredto control an adjustment of an amount of electrical energy fromelectrical power distribution system 10 that charger 18 uses to chargerechargeable battery 16 at different moments in time using priceinformation for the electrical energy. Controller 20 may access theprice information for electrical energy, for example, via priceinformation source 22.

In some embodiments, controller 20 may automatically access the priceinformation without user intervention and may control an adjustment ofan amount of electrical energy that charger 18 uses to chargerechargeable battery 16 automatically and without user intervention.

In one embodiment, controller 20 uses the price information to reduce acost of charging rechargeable battery 16 compared with arrangementswhich do not perform the controlling of the adjustment using the priceinformation. For example, controller 20 may reduce a cost of chargingrechargeable battery 16 as compared to a battery charging apparatus thatis not aware of the price information by enabling charger 18 to chargerechargeable battery 16 during portions of a period of time when theprice of the electrical energy is lowest and reducing charging or notcharging vehicle 34 when costs of electrical energy are higher.

Controller 20 may control charger 18 to charge rechargeable battery 16using different amounts of electrical energy at different moments intime using the price information. For example, at one moment in time(e.g., at a time when the price of the electrical energy increases),controller 20 may ceasing the charging. Furthermore, controller 20 maycontrol charger 18 to charge rechargeable battery 16 using an increasedamount of electrical energy at a first of the different moments in timecompared with a second of the different moments in time as a result ofthe price of the electrical energy being less at the first of thedifferent moments in time compared with the second of the differentmoments in time. For example, controller 20 may configure charger 18 tocharge at 50% of a maximum rate at one moment in time when theelectrical energy is available at a first price and later configurecharger 18 to charge at 90% of a maximum rate at a second moment in timewhen the electrical energy is available at price lower than the firstprice. In another example, the charger may cease charging altogetherwhen the price of electrical energy is elevated and may charge using amaximum amount of electrical energy when the price of electrical energyis lower.

As discussed above, the price information may include different pricesof the electrical energy at the different moments in time. For example,the price information may indicate hourly prices, at least some of whichare different relative to one another, over a twenty-four hour period.Controller 20 may increase and/or decrease the amount of the electricalenergy used to charge rechargeable battery 16 at the different momentsin time as a result of the different prices. The price information mayinclude one or more projected prices over a future period of time andcontroller 20 may control charger 20 based on the one or more projectedprices at respective moments of the future period of time. In someconfigurations, controller 20 may receive the price information fromelectrical power distribution system 10.

In some cases, controller 20 may receive an update changing one of theone or more projected prices and may adjust the amount of the electricalenergy as a result of the receiving of the update. The update to theprojected price may result from a change in electrical powerdistribution system 10. For example, if an amount of power availablefrom electrical power distribution system 10 suddenly changes (e.g.,because a power generation source is disabled or a major transmissionline is disabled or because an on-site generator has been activated),the projected price may change accordingly (e.g., the price maydrastically increase because supply is low and demand is high). In oneembodiment, if a price update changes the previously projected price,the controller may alter the charging (e.g., reduce or cease charging ifcost increases or increase charging if cost decreases).

In one embodiment, controller 20 may access information describing adesired future point in time for rechargeable battery 16 to be chargedto a desired state. For example, controller 20 may access theinformation via user interface 28. Controller 20 may control charger 18so that rechargeable battery 16 reaches the desired state by the desiredfuture point in time. Furthermore, controller 20 may determine ananticipated amount of time to charge rechargeable battery 16 based on acurrent state of charge of rechargeable battery 16 and may controlcharger 18 as a result of the determining of the anticipated amount oftime.

In some arrangements, controller 20 may control climate system 36. Doingso may include controller 20 estimating an amount of time to be consumedby climate system 36 to bring a temperature of electrical vehicle 34 toa desired temperature. In one embodiment, controller 20 may control anamount of the electrical energy consumed by charger 18 at the differentmoments in time based on the estimated amount of time to be consumed byclimate system 36 to avoid climate system 36 being enabledsimultaneously with charger 18.

Referring to FIG. 4, a method of charging a rechargeable battery isillustrated according to one embodiment. Although FIG. 4 depicts actionsof the method arranged in a particular way, other embodiments of themethod are possible including embodiments including additional or feweractions than illustrated in FIG. 4 and/or actions performed in adifferent order than illustrated in FIG. 4. Below, the method of FIG. 4is described as being implemented by controller 20. However, otherembodiments are possible in which other circuitry apart from controller20 may perform the method. Furthermore, FIG. 4 is described with respectto a vehicle application. The method may alternatively be applied toother applications which include rechargeable battery 16 other thanvehicle applications.

At an act A10, controller 20 accesses price information, for example, byreceiving the price information from price information source 22. In oneembodiment, the price information may include prices of electricalenergy from electrical power distribution system 10 for a future periodof time (e.g., for the next twenty-four hours). The period of time maybe broken down into intervals (e.g., one-hour intervals) and the priceinformation may include a price for each of the intervals. In addition,the price information may include instantaneous updates in oneembodiment. Some or all of the prices may be different from one another.

At an act A12, controller 20 accesses other information associated withcharging rechargeable battery 16. The other information may include acurrent state of charge of rechargeable battery 16 (e.g., 20% charged),which controller 20 may retrieve from charger 18 in one embodiment.Controller 20 may also access information describing a desired state ofcharge (e.g., 100% charged), which may be provided by a user (e.g., viauser interface 28). Controller 20 may also access information describinga future time by which rechargeable battery 16 should be charged to thedesired state of charge. This information may be provided by a user, andin one configuration controller 20 may access this information via userinterface 28 or storage circuitry 24.

In one embodiment, controller 20 may access information describing anenergy storage capacity of rechargeable battery 16 (e.g., 14 kWh) andinformation describing an amount of power that electrical powerdistribution system 10 may deliver to battery charging apparatus 14(e.g., 1 kW). In some cases, the amount of power may be related to theamperage rating of a circuit breaker through which the electrical energyflows. For example, if electrical power distribution system 10 deliverselectrical energy at 120 V through a 15 A circuit breaker, the amount ofpower may be 1.4 kW.

At an act A14, controller 20 may determine whether vehicle 34 should bepre-heated or pre-cooled. In one embodiment, a user may indicate (e.g.,via user interface 28) that the vehicle should be brought to a desiredtemperature by a future time. Alternatively or additionally, controller20 may determine whether rechargeable battery 16 should be pre-heated orpre-cooled prior to or while charger 18 charges rechargeable battery 16.

At an act A16, if vehicle 34 is to be pre-heated or pre-cooled,controller 20 accesses temperature information describing the desiredtemperature of the cabin and/or a desired temperature of rechargeablebattery 16. In one embodiment, controller 20 may also access informationdescribing one or more current temperatures of vehicle 34, for example,from an onboard temperature sensing device.

At an act A18, controller 20 may use the desired temperature and thecurrent temperature to estimate an amount of time that it will take forclimate system 36 to bring the temperature of vehicle 34 to the desiredtemperature.

At an act A20, controller 20 may determine whether a user desires tocharge rechargeable battery 16 immediately. If so, controller 20 mightnot use the price information in controlling charger 18. Instead,controller 20 may simply enable charger 18.

At an act A22, controller 20 may use some or all of: the priceinformation accessed in act A10, the other information accessed in A12,and the estimated time determined in act A18 to optimize a cost ofcharging rechargeable battery 16. Optimizing the cost may includereducing the cost of charging as compared with a method of charging inwhich the price information is not considered. Optimizing the cost mayalso include minimizing the cost so that the cost is the lowest possiblecost of charging rechargeable battery 16 that can be achieved within thefuture period of time associated with the price information (e.g., thenext twenty-four hours) and to meet the user's expectations. Controller20 may optimize the cost by controlling charger 18 to chargerechargeable battery 16 during the intervals of the future period oftime associated with the price information having the lowest pricesrelative to other intervals of the future period of time.

In one embodiment described below, controller 20 may use a constraintequation and a method of minimizing a linear problem to optimize thecost. Other formulas and techniques of optimizing a cost mayalternatively be used.

At an act A24, as a result of the optimizing of the cost, controller 20may determine a schedule specifying when and how much electrical energycharger 18 should use to charge rechargeable battery 16. In oneembodiment, the schedule may specify a subset of the intervals of thefuture period associated with the price information during which charger18 should charge rechargeable battery 16 in order to optimize cost. Forexample, if the future period consists of price information fortwenty-four intervals, controller 20 may determine that charger 18 willneed six of the intervals to charge rechargeable battery 16 to thedesired state of charge and that charger 18 needs to complete the chargeby the nineteenth interval. Controller 20 may then determine (e.g.,using the method described below) which six of the eighteen intervalsoccurring prior to the start of the nineteenth interval should be usedto charge rechargeable battery 16. Controller 20 may use the priceinformation to make this determination in one embodiment.

The schedule may also specify the amount of electrical energy charger 18uses to charge rechargeable battery 16. For example, controller 20 maydetermine that charger 18 should use one amount of electrical energyduring some of the intervals and a lower amount of electrical energyduring others of the intervals.

For example, someone may connect electrical vehicle 34 to electricalpower distribution system 10 (e.g., via battery charging apparatus 14)at 6:00 PM after returning home from work and may specify (e.g., viauser interface 28) that electrical vehicle 34 (i.e., rechargeablebattery 16) is to be recharged to full capacity by 6:30 AM (i.e., adesired future point in time). Controller 20 may communicate withcharger 18 to determine a current state of charge of rechargeablebattery 16. Using the current state of charge, a capacity ofrechargeable battery 16, and a rate at which battery charging apparatus14 can receive electrical energy from electrical power distributionsystem 10 (e.g., 1.4 kW for a 120 Volt/15 Amp line) controller 20 maydetermine that charging rechargeable battery 16 will be cheapest between10:00 PM and 4:00 a.m.

In one embodiment, controller 20 may use the time estimate determined inact A18 in developing the schedule. In some configurations, theaggregate power drawn by the combination of charger 18 and climatesystem 36 may exceed a rate at which electrical power distributionsystem 10 may deliver electrical energy to battery charging apparatus 14and climate system 36, potentially tripping a circuit breaker.Accordingly, in some embodiments, controller 20 may determine thecharging schedule so that charger 18 and climate system 36 are notsimultaneously enabled. In one embodiment, controller 20 may develop theschedule so that climate system 36 brings a temperature of vehicle 34 toa desired temperature just before a future time specified by the user,anticipating that the user may use vehicle 34 at the future time.Accordingly, the schedule may indicate that charger 18 completescharging prior to a time when climate system 36 is enabled.

In one embodiment, controller 20 may determine the charging schedule sothat charger 18 charges at a reduced amount of electrical energy so thatthe aggregate power drawn by charger 18 and climate system 36 does notexceed the rate at which electrical power distribution system 10 maydeliver electrical energy to battery charging apparatus 14 and climatesystem 36. In this embodiment, charger 18 and climate system 36 may bothbe operational simultaneously.

If controller 20 previously determined at act A20 that charger 18 shouldimmediately begin charging rechargeable battery 16, the scheduledetermined at act A24 may simply indicate that charger 18 should startcharging immediately.

At an act A26, controller 20 may control charger 18 according to theschedule determined by controller 20. Controlling charger 18 may includeenabling charger 18, disabling charger 18, and/or adjusting an amount ofelectrical energy which charger 18 uses to charge rechargeable battery16 when charger 18 is enabled. If the schedule includes enabling climatesystem 36, act A26 may also include controller 20 controlling climatesystem 36.

In some configurations, controller 20 may receive updates to previouslyreceived price information during the period associated with previouslyreceived price information. These updates may replace the previouslyreceived price information. For example, an update may indicate a newprice or prices for three of the intervals of the period. An operator ofelectrical power distribution system 10 may use the updates to quicklyincrease a price due to an event affecting the operator's ability tosupply electrical energy. For example, if a major transmission line isdisabled, the operator may quickly and substantially raise the price forintervals of the period as a way of discouraging consumption ofelectrical energy during a time when the operator's ability to supplythe electrical energy is hampered by the disabled transmission line.

If controller 20 receives a price update, controller 20 may repeat oneor more of the acts of FIG. 4 in response to receiving the price update.For example, controller may access the updated price at act A10, mayrepeat the optimization of the charging cost at act A22, may revise thecharging schedule at act A24, and may execute the revised chargingschedule at act A26.

One embodiment of a method of minimizing a cost of charging is describedbelow. Other formulas and techniques for optimizing a cost mayalternatively be used in other embodiments.

One embodiment of a method using a constraint equation and a method ofminimizing a linear problem to optimize charging cost is describedbelow. Controller 20 may use this method to optimize a charging cost.Other methods and/or techniques for optimizing a charging cost mayalternatively be used by controller 20 in other embodiments.

Optimizing the cost of charging rechargeable battery 16 may beformulated as the following linear programming problem:

minimize

Z=c _(i) p _(i)(2.4a)   (Equation 1)

subject to the constraint:

A _(n,m) p _(n) ≦b _(m)(2.4a)   (Equation 2)

The objective function can be written as:

$\begin{matrix}{Z = {\sum\limits_{i = 1}^{24}{c_{i}p_{i}\Delta \; t}}} & \left( {{Equation}\mspace{14mu} 3} \right)\end{matrix}$

where Z is the cost of electricity consumed over a 24-hour period, c_(i)is the cost of electricity in hour i in $/kWh, p_(i) is the averagepower delivered to charger 18 in hour i in kW, and Δt is one hour.

Regarding the constraint equation, b_(m) is a the maximum power that canbe drawn from a connection to electrical power distribution system 10(e.g., 1.4 kW for a 120 Volt/15 Amp connection), A_(n,m) is diagonalmatrix of 1's, and p_(n) is the average power delivered to charger 18 inhour n in kW.

In some cases, there may be only one constraint equation that constrainsrechargeable battery 16 to reach a desired state of charge (SOC) (e.g.,50% charged, 75% charged, 100% charged, etc.) at a user-specified time.The constraint matrix becomes a (1,24) matrix. The constraint equationmay be written as follows:

$\begin{matrix}{{{S\; O\; C_{initial}} + {\frac{1}{{cap}_{bat}}{\sum\limits_{i = 1}^{n}{p_{i}\Delta \; t}}}} = {S\; O\; C_{end}}} & \left( {{Equation}\mspace{14mu} 4} \right)\end{matrix}$

or rearranged:

$\begin{matrix}{{\sum\limits_{i = 1}^{n}{p_{i}\Delta \; t}} = {\left( {{S\; O\; C_{end}} - {S\; O\; C_{initial}}} \right) \cdot {cap}_{bat}}} & \left( {{Equation}\mspace{14mu} 5} \right)\end{matrix}$

where cap_(bat) is the capacity of rechargeable battery 16,SOC_(initial) is the initial state of charge of rechargeable battery 16(e.g., 10%), and SOC_(end) is the desired SOC (e.g., 100%).

There are the following bounds on the decision variable

0≦p_(i)≦p_(max)   (Equation 6)

where p_(max) is the maximum charging power that can be drawn from aconnection to electrical power distribution system 10 (e.g., 1.4 kW fora 120V/15 A supply) and cap_(bat) is the rated energy capacity ofrechargeable battery 16 in kWh.

From a computational point of view, it may be practical tonon-dimensionalize the optimization problem. The followingnon-dimensional variables may be defined:

$\begin{matrix}{p^{*} = \frac{p}{p_{\max}}} & \left( {{Equation}\mspace{14mu} 7} \right) \\{c^{*} = \frac{c}{c_{\max}}} & \left( {{Equation}\mspace{14mu} 8} \right) \\{{\Delta \; t^{*}} = \frac{\Delta \; t}{\Delta \; t_{0}}} & \left( {{Equation}\mspace{14mu} 9} \right)\end{matrix}$

Accordingly, the non-dimensional objective function can be re-writtenas:

$\begin{matrix}{Z^{*} = {\frac{Z}{c_{\max}p_{\max}\Delta \; t_{0}} = {\sum\limits_{i = 1}^{24}{a_{i}p_{i}^{*}}}}} & \left( {{Equation}\mspace{14mu} 10} \right)\end{matrix}$

with the non-dimensionalized cost coefficient

a_(i)=Δt*c_(i)*   (Equation 11)

and the non-dimensionalized constraint equation may be rewritten as:

$\begin{matrix}{{\sum\limits_{i = 1}^{n}p_{i}^{*}} = {\left( {{S\; O\; C_{end}} - {S\; O\; C_{initial}}} \right) \cdot \frac{{cap}_{bat}}{p_{\max}\Delta \; t^{*}\Delta \; t_{0}}}} & \left( {{Equation}\mspace{14mu} 12} \right)\end{matrix}$

with the bounds on the non-dimensional variables

0≦p_(i)*≦1   (Equation 13)

Many different techniques may be used to solve the linear optimizationproblem including the technique described in Chapter 10 of the book“Numerical Recipes, The Art of Scientific Computing,” CambridgeUniversity Press, 1988, which is incorporated herein by reference.

According to this technique, the following arrays and variables areassigned:

-   M: number of constraint equations. Here M=1;-   N: number of decision variables: Here assume first 24 decision    variables to represent the 24 hourly problem space. The time    variable may be reduces, of course, for example to 15 minutes rather    than an hour. In this example, N=24.-   NP=N+1;-   MP=M+2;-   A: the constraint matrix. it also contains the objective function.    The size of the constraint matrix is (M+2, N+1);-   A(1,n+1 . . . NP)=coefficient of objective function-   A(2,n+1 . . . NP)=constraint coefficient. This may be the resting    time (the time that rechargeable battery 16 is connected to    electrical power distribution system 10 and is available for    charging).    In one example, the following non-dimensionalized variables may be    used:

TABLE A Non-dimensionalized variables Non-dimensionalize C* = C/Cmax dt*= dt/dt0 define Cmax = $1 1 $ dt0 = 1 hour 1 hour dt 1 hour dt* 1 Pmax1.4 kW Cap 14 kWh

Then, the following power rates and resting time of the vehicle may beused. The values in the time column represent intervals of a timeperiod. Resting time is time during which rechargeable battery 16 may becharged. In Table B, a “1” indicates that rechargeable battery 16 may becharged during the interval and a “0” indicates that rechargeablebattery 16 may not be charged during the interval. In one embodiment,intervals 7:00 through 12:00 may be outside of the resting time becausea user may have specified 7:00 as a desired time of charge completion.Accordingly, controller 20 may determine a schedule so that chargingdoes not take place during the intervals from 7:00 through 12:00.

TABLE B Rates and TOU rate and resting time. Electric Time Rates[$/kWh]Non-dimensionalized rate (C*) Resting time 13:00 0.0772 0.0772 0 14:000.0772 0.0772 0 15:00 0.0772 0.0772 0 16:00 0.0772 0.0772 1 17:00 0.07720.0772 1 18:00 0.0772 0.0772 1 19:00 0.0452 0.0452 1 20:00 0.0452 0.04521 21:00 0.0452 0.0452 1 22:00 0.0452 0.0452 1 23:00 0.0358 0.0358 1 0:00 0.0358 0.0358 1  1:00 0.0358 0.0358 1  2:00 0.0358 0.0358 1  3:000.0358 0.0358 1  4:00 0.0358 0.0358 1  5:00 0.0358 0.0358 1  6:00 0.03580.0358 1  7:00 0.0452 0.0452 0  8:00 0.0452 0.0452 0  9:00 0.0452 0.04520 10:00 0.0452 0.0452 0 11:00 0.0452 0.0452 0 12:00 0.0772 0.0772 0So that:

-   A(1, . . . )=(0, 0.0772, 0.0772, 0.0772, 0.0772, 0.0772, 0.0772,    0.0452, . . . 0.0772);-   A(2, . . . )=(10, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,    1, 0, 0, 0, 0, 0, 0); and-   cap/pmax/dt*/dt0=14 kWh/1.4 kW/1 h/1=10.

Referring to FIG. 5A, results of the optimization example describedabove in relation to Tables A and B are illustrated. FIG. 5A illustratesprice information associated with electrical energy provided byelectrical power distribution system 10. Note that the prices are lowerduring nighttime hours.

Referring to FIG. 5B, a resting time associated with the exampledescribed above in relation to Tables A and B is illustrated. Note thataccording to the resting time, rechargeable battery 16 is available forcharging between the hours of 15:00 and 7:00.

Referring to FIG. 5C, a charging schedule associated with the exampledescribed above in relation to Tables A and B is illustrated. Note thatthe schedule indicates that the most cost effective time to chargerechargeable battery 16 is between 20:00 and 7:00.

Referring to FIG. 5D, a modified version of the charging schedule ofFIG. 5C is illustrated. The charging schedule of FIG. 5C has beenmodified to allow time for climate system 36 to bring vehicle 34 to adesired temperature prior to 7:00. According to the modified chargingschedule, the most cost effective time to charge rechargeable battery 16in view of the need to bring vehicle 34 to the desired temperature isbetween 19:00 and 6:00.

Referring to FIG. 5E, a schedule associated with climate system 36 isillustrated. According to the schedule, controller 20 should enableclimate system 36 starting at 6:00 and disable climate system 36 at 7:00to bring vehicle 34 to the desired temperature by 7:00.

In compliance with the statute, embodiments of the invention have beendescribed in language more or less specific as to structural andmethodical features. It is to be understood, however, that the entireinvention is not limited to the specific features and/or embodimentsshown and/or described, since the disclosed embodiments comprise formsof putting the invention into effect. The invention is, therefore,claimed in any of its forms or modifications within the proper scope ofthe appended claims appropriately interpreted in accordance with thedoctrine of equivalents.

1. A battery charging control method comprising: accessing priceinformation of electrical energy supplied by an electrical powerdistribution system; and controlling an adjustment of an amount of theelectrical energy from the electrical power distribution system which isused to charge a rechargeable battery at different moments in time usingthe price information.
 2. The method of claim 1 wherein the controllingcomprises using the price information to reduce a cost of charging therechargeable battery compared with arrangements which do not perform thecontrolling of the adjustment using the price information.
 3. The methodof claim 1 wherein the controlling comprises charging using differentamounts of the electrical energy from the electrical power distributionsystem at the different moments in time using the price information. 4.The method of claim 3 wherein the controlling comprises ceasing thecharging at one of the different moments in time.
 5. The method of claim3 wherein the controlling comprises charging using an increased amountof the electrical energy at a first of the different moments in timecompared with a second of the different moments in time as a result ofthe price of the electrical energy being less at the first of thedifferent moments in time compared with the second of the differentmoments in time.
 6. The method of claim 1 wherein the accessingcomprises accessing the price information comprising different prices ofthe electrical energy at the different moments in time and thecontrolling comprises increasing and decreasing the amount of theelectrical energy used to charge the rechargeable battery at thedifferent moments in time as a result of the different prices.
 7. Themethod of claim 1 wherein the accessing comprises accessing the priceinformation including one or more projected prices over a future periodof time and the controlling comprises controlling the adjustment basedon the one or more projected prices at respective moments of the futureperiod of time.
 8. The method of claim 7 further comprising receiving anupdate changing one of the one or more projected prices and thecontrolling comprises adjusting the amount of the electrical energy as aresult of the receiving of the update.
 9. The method of claim 1 whereinthe accessing comprises receiving the price information from theelectrical power distribution system.
 10. The method of claim 1 furthercomprising accessing information describing a desired future point intime for the rechargeable battery to be charged to a desired state andwherein the controlling comprises controlling so that the rechargeablebattery reaches the desired state by the desired future point in time.11. The method of claim 1 further comprising determining an anticipatedamount of time to charge the rechargeable battery based on a currentstate of charge of the rechargeable battery and wherein the controllingcomprises controlling as a result of the determining of the anticipatedamount of time.
 12. An electrical vehicle charging method comprising:coupling an electrical vehicle having a depleted state of charge with anelectrical power distribution system; accessing price information forelectrical energy of the electrical power distribution system; chargingthe electrical vehicle using the electrical energy of the electricalpower distribution system; and controlling an amount of the electricalenergy consumed by the charging of the electrical vehicle at differentmoments in time using the price information.
 13. The method of claim 12wherein the charging comprises charging at different rates at thedifferent moments in time based on the price information.
 14. The methodof claim 13 wherein the controlling comprises ceasing the charging atone of the different moments in time.
 15. The method of claim 13 whereinthe charging comprises charging using an increased amount of theelectrical energy at a first of the different moments in time comparedwith a second of the different moments in time as a result of the priceof the electrical energy being less at the first of the differentmoments in time compared with the second of the different moments intime.
 16. The method of claim 12 wherein the accessing comprisesaccessing the price information comprising different prices of theelectrical energy at the different moments in time and the controllingcomprises increasing and decreasing an amount of the electrical energyconsumed by the charging at the different moments in time as a result ofthe different prices.
 17. A battery charging control apparatuscomprising: processing circuitry configured to: access price informationof electrical energy supplied by an electrical power distributionsystem; and control an adjustment of an amount of the electrical energyfrom the electrical power distribution system used to charge arechargeable battery at different moments in time using the priceinformation.
 18. The apparatus of claim 17 wherein the price informationcomprises different prices of the electrical energy at the differentmoments in time and the processing circuitry is configured to increaseand decrease the amount of the electrical energy used to charge therechargeable battery at the different moments in time as a result of thedifferent prices.
 19. The apparatus of claim 17 wherein the priceinformation includes one or more projected prices over a future periodof time and the processing circuitry is configured to control theadjustment based on the one or more projected prices at respectivemoments of the future period of time.
 20. The apparatus of claim 19wherein the processing circuitry is configured to receive an updatechanging one of the one or more projected prices and to control theadjustment of the amount of the electrical energy as a result ofreceiving the update.
 21. An electrical vehicle comprising: arechargeable battery; a charger configured to consume electrical energyfrom an electrical power distribution system to charge the rechargeablebattery; and a controller configured to: access price information of theelectrical energy supplied by the electrical power distribution system;and control an amount of the electrical energy from the electrical powerdistribution system consumed by the charger at different moments in timeusing the price information.
 22. The vehicle of claim 21 furthercomprising a climate system configured to heat and/or cool theelectrical vehicle and wherein the controller is configured to: estimatean amount of time to be consumed by the climate system to bring atemperature of the electrical vehicle to a desired temperature; andusing the estimated amount of time, control the amount of the electricalenergy consumed by the charger at the different moments in time.
 23. Thevehicle of claim 21 wherein the controller is configured to use theprice information to reduce a cost of charging the rechargeable batterycompared with arrangements which do not control the adjustment of theamount using the price information.
 24. The vehicle of claim 21 whereinthe controller is configured to control the charger to charge therechargeable battery using different amounts of electrical energy at thedifferent moments in time using the price information.
 25. The vehicleof claim 24 wherein the controller is configured to control the chargerto charge using an amount of electrical energy at a first of thedifferent moments in time compared with a second of the differentmoments in time as a result of the price of the electrical energy beingless at the first of the different moments in time compared with thesecond of the different moments in time.
 26. The vehicle of claim 21wherein the controller is configured to access information describing adesired future point in time for the rechargeable battery to be chargedto a desired state and to control the charger so that the rechargeablebattery reaches the desired state by the desired future point in time.27. The vehicle of claim 22 wherein the controller is configured to usethe price information to reduce a cost of charging the rechargeablebattery compared with arrangements which do not control the adjustmentof the amount using the price information.
 28. The vehicle of claim 22wherein the controller is configured to control the charger to chargethe rechargeable battery using different amounts of electrical energy atthe different moments in time using the price information.
 29. Thevehicle of claim 22 wherein the controller is configured to accessinformation describing a desired future point in time for therechargeable battery to be charged to a desired state and to control thecharger so that the rechargeable battery reaches the desired state bythe desired future point in time.